The published UV/optical flux ratios plotted as grey circles in Figure 1 do not include allowance for the uncertain contribution of the host galaxy starlight to the optical continuum flux. For NGC 5548 the starlight contribution to the optical flux is known [1]}. We therefore plotted NGC 5548 in Figure 1 twice, once using the uncorrected optical flux (the filled circle) to match the uncorrected ratios for the other AGNs, and once with the starlight subtracted (the filled square). We have taken average values of the two ratios from [2]} and [3]} from the 1988-1989 International AGN Watch campaign. The uncertainty in the starlight correction for the AGNs in general is the main uncertainty in using the UV/optical continuum ratio to estimate reddenings. The separation between the two NGC 5548 points in Figure 1 gives an indication of the errors. From Figure 1, \(E(1337-5100) = 1.09 \pm 0.26\)  where the uncertainty is the uncertainty in the host galaxy starlight subtraction. It is interesting that if the points for the other AGNs (the grey circles) are shifted to the right because of an approximately similar starlight correction as for NGC 5548, the start of the reddening vector is at \(\log F_{1337}/F_{5100} \sim 0.2\)  which is the ratio predicted if an \(F_{\nu } \propto \nu ^{1/3}\)  spectrum continues to \(\sim 1300\) .
